1. Field of the Invention
One or more aspects of the present invention relate generally to computer generated graphics, and more particularly to N-patches for forming computer graphic images.
2. Description of the Related Art
In graphics processing, it is well-known to generate a surface represented by a number of interconnected polygons. Conventionally, such polygons are triangles though other geometric shapes may be used.
To describe three-dimensional (3D) objects, High Order Surface (HOS) technologies may be employed. Rather, than using polygons of first order surfaces, linear or flat surfaces, to describe curved lines of 3D objects, an HOS technology is used. An example of an HOS technology is an N-patch, though there are other types of HOS technologies, such as polynomial surfaces. For an N-patch, vectors normal (“normals”) to a surface to be imaged at corners (vertices) of a triangle are conventionally used.
A problem with N-patches that share an edge is that a gap between shared edges can result when normal vectors along a shared edge are not equal. To fill such a gap, it may be tessellated with polygons. However, a tessellated gap often causes unwanted smoothing or smearing artifacts. Accordingly, it would be both desirable and useful to generate a shared N-patch edge that results in less unwanted smoothing or smearing than a prior N-patch shared edge. Furthermore, it would be both desirable and useful to generate a shared N-patch edge that exhibits fewer artifacts than a prior shared N-patch edge.